archusvijay1
Member level 3
Hi,
I am working on a custom SIM800 board and the circuit is attached along with this. I've tested the circuit here and was working fine. My application uses HTTP get method to send the sensor data to a web server. When I installed the device in field which is actually inside a metal cabin it stopped working. The device got connected to GPRS when the metal cabin is opened. So I replaced the antenna with a higher capacity antenna but same effect. It is not connecting when the cabin is closed. Then I've replaced the entire module with a new modem and it got connected even with closed cabin.
Later upon checking the modem with AT commands I could get responses for sim detection commands and all. Also when I checked for signal strength using AT commands the signal strength values got changed with and without antenna. Strange thing is that I could get signal strength parameter even without inserting sim card. How does it happen? Can someone tell me what would be the problem? Is the power supply section is correct? I removed the zener diode in actual circuit as the LM317 starts heating up badly.
I am working on a custom SIM800 board and the circuit is attached along with this. I've tested the circuit here and was working fine. My application uses HTTP get method to send the sensor data to a web server. When I installed the device in field which is actually inside a metal cabin it stopped working. The device got connected to GPRS when the metal cabin is opened. So I replaced the antenna with a higher capacity antenna but same effect. It is not connecting when the cabin is closed. Then I've replaced the entire module with a new modem and it got connected even with closed cabin.
Later upon checking the modem with AT commands I could get responses for sim detection commands and all. Also when I checked for signal strength using AT commands the signal strength values got changed with and without antenna. Strange thing is that I could get signal strength parameter even without inserting sim card. How does it happen? Can someone tell me what would be the problem? Is the power supply section is correct? I removed the zener diode in actual circuit as the LM317 starts heating up badly.